Refrigerating means for dough mixers



1949- M. A. STICELBER REFRIGERATING MEANS FOR DOUGH MIXERS 2Sheets-Sheet 1 Filed March '24, 1945 INVENTOR.

MERLIN A. STICELBER ATTORNEY Feb. 8, 1949. M. A. STICELBER REFRIGERATINGMEANS FOR DOUGH MIXERS 2 Sheets-Sheet 2 Filed March 24, 1945 MIA? mum"on I INVENTOR. MERLIN A. STICELBER ATTORNEY i Patented Feb. 8, 1949UNITED STATES PATENT OFFICE Merlin A. Sticelber, Kansas ,City, Mo.,

asslgnor to Quilt-Seal, Inc., a corporation of Missouri ApplicationMarch 24, 1945, Serial No. 584,677

4 Claims. 1

My invention relates to dough mixers, and more particularly torefrigerating means for dough mixers.

It is a purpose of my invention to provide means for cooling the wall ofa dough mixer, that is so constructed and arranged as to avoid thefrequent cycling of the compressor that is experienced with directexpansion refrigerating means for dough mixer walls as existed prior tomy present invention.

This is accomplished by providing temperature responsive controllingmeans in a heat transfer medium that is in heat transfer relation bothto a direct expansion refrigerating coil and the wall of the dough mixerthat is to be cooled. It has been previously the custom to mounttemperature responsive controlling means for the refrigerating means forthe dough mixer wall in contact with the wall that is being cooled, sothat the temperature of said wall controls the operation of saidtemperature responsive means. This is an extremely sensitive control.

Temperature changes in the wall will'cause the thermostatic controllingdevice to be operated to halt the operation of the compressor when apredeterm ned low temperature of the wall has been reached, and upon thetemperature of the wall rising again due to the heating action of thecontents of the mixer, the c rcuit controlling the operation of thecompressor is thereupon closed by the temperature responsive means onthe wall of the dough mixer, setting the compressor in operation, if theusual pressure responsive means cooperating with said temperatureresponsive means is in circuit c'OSing position, whereupon thetemperature of the wall is again lowered to the point at which saidtemperature responsive controlling means again opens the circuit, thisalternate opening and closing of the circu t being repeated severaltimes during each period of operation of the dough mixer. While thetemperature can be controlled within the closest limits in this manner,the frequent cycl ng of the compressor is sometimes found to beobjectionable and this can be avoided by placing the temperatureresponsive controlling means as above set forth.

When said temperature responsive cooling means is placed with the bulbthereof in contact with the heat transfer medium, preferably, a liquid,the circuit will not be opened and closed frequently through saidcontrolling means by slight temperature changes in the wall of the doughmixer, but the temperature of the heat 2 therein being only inaccordance with relatively greater changes in the temperature of thedough mixer wall, thus keeping the compressor in operation continuouslyfor a longer period of time during the mixing of each batch of dough,and making only one such period-of operation of the compressor.necessary ordinarily during each such mixing period. In practice, thedough mixerwall is kept at a low temperature between mixing operations,and ordinarily the temperature responsive control, when used inaccordance with the present invention, is in an open circuit conditionat the time mixing of dough commences With the bulb of the temperatureresponsive controlling means in contact with the heat transfer mediumprovided as above mentioned the large body of said heat transfer mediumwill not immediately rise in temperature, as does the wall of the doughmixer when the warm dough comes in contact therewith, but will transferheat from the dough mixer wall, keeping the temperature of the wall fromrising as rapidly as would otherwise be the case, and the relativelylarge mass of heat transfer medium will gradually warm up until such atemperature is reached that the temperature responsive controllingmeans-willclose the circuit. provided of course, that the pressureresponsive switching means is also in closed circuit position at thattime. Thereupon the compressor will be set in operation and willcontinue to operate ordinarily through a large fraction of the t me thatthe mixing operation continues, said compressor ordinarily being haltedby the opening of the circuit through the controlling device responsiveto the temperature of the heat transfer medium above referred to. Due tothe fact that the dough mixer wall will be at a temperatureapproximately that of said heat transfer medium at the time saidcompressor is halted, and the mass of the transfer medium will lagsomewhat behind the cold heat transfer medium is so much greater thanthat of the wall in contact therewith, the heat transfer medium willordinarily not again reach a temperature during said mixing operationthat will cause the crcuit to be closed through the temperatureresponsive controlling device, and accordingly the compressor will notordinarily operate aga n during such mixing operation. In case it isagain set in operation, such operation will continue long enough that nothird period of operation of the compressor is ever found to benecessary.

While, preferably, a liquid heat transfer medium is provided around thecooling coil in a Jacket that is provided on the outer face of the doughmixer wall that is to be cooled, it is only absolutely necessary thatthe heat transfer medium be in a liquid condition at a temperature atwhich it would be inserted in the jacket and that upon cooling thereofit will not expand so as to cause damage to the jacket. Thus a materialcould be used that would be in a liquid state at ordinary roomtemperatures or even at a temperature approximating the freezing pointof water, which would solidify at or near the freezing point of water,or therebelow, and would ordinarily be solid at the temperatures atwhich the wall of the dough mixer and the cooling coil are kept duringthe operation of the device, as long as in solidifying said materialwould not expand.

The jacket is, preferably. provided with a fill opening at its uppermostpoint, which is left constantly open, so that in case my invention isapplied to a dough mixer which is moved from one position to another andthe heat transfer material remains in a liquid state while therefrigerating means is in operation, a hydraulic hammer will not beformed by said liquid upon tilting or otherwise moving the dough mixerbowl from one position to another.

Other objects and advantages of my invention will appear as thedescription of the drawings proceeds. I desire to have it understood,however, that I do not intend to limit myself to the particular detailsshown or described, except as defined in the clainis.

Fig. 1 is a diagrammatic view showing my improved refrigerating meansfor a dough mixer.

Fig. 2 is a fragmentary view partly in elevation and partly in section,showing a portion of the jacket and expansion coil. 7

Fig. 3 is a vertical sectional view through a portion of the jacket,showing the preferred form of expansion coil used in carrying out myinvention,

and

Fig. 4 is a view similar to Fig. 3 of a modification. w

Referring in detail to the drawings, my improved refrigerating means fordough mixers is shown as being applied to a dough mixer Ill, which isprovided with an agitator l I having beater arms II, which may be of anydesired character, I rotating about a shaft l3 ,as an axis and causingthe dough in the bowl of the mixer to be engaged with a wall Irepeatedly as the mixing operation.

continues, said wall being cooled in a manner to be described below.While a type of dough mixer is shown inthe drawing that has a movablewall l5 through which the contents of the mixer are discharged, anyother type of mixer, such as the commonly provided types that tilt aboutthe shaft l3 as an axis, can be cooled in a similar manner.

A conventional form of refrigerating system is illustrated, comprising acompressor l6 connected with a condenser l1 through a conduit l8, whichin turn is connected with a receiver is through a.

conduit 20. The conduit 2| extends from the receiver to a manuallyoperatedcontrol valve 22, from which the conduit 23 leads into the inletend of an expansion coil through an expansion device 24. From the otherend of said expansion coil a suction pipe, or return conduit 25 extendsto the intake port of the compressor I 6. An electro-magnetic valve 26is, preferably, interposed in the suction pipe 25, as is also a T 21 forconnecting a pressure responsive switch 28 with said suction line. Theelectro-magnetic switch 25 is of the type that is held in open positionby means of a solenoid provided therein, when electrical energy issupplied thereto.

substantially semi-cylindrical in cross section thereon. said membersbeing welded at their longitudinal edges to the outer face of the wallit at 30. so as to provide a liquid tight joint therebetween, thusproviding a plurality of parallel refrigerant conduits 3| extendingtransversely of said wall, the adjacent conduits being connectedtogether by means of connecting portions 32, as will be evident fromFig. 2, to provide a conduit following a circuitous path along said wallfrom the inlet end thereof to the conduit 33, which issimilarlyconstructed to the lengths of conduit 3|, but runsperpendicularly thereto, to provide a return conduit leading tothesuction pipe 25 which is connected with the expansion coil at thedischarge end thereof adjacent the inlet connection from the expansionvalve 24. Said conduit 33 is spaced from the connecting portions 32 ofthe expansion coil and the parallel runs or lengths 3| of the expansioncoil are spaced from each other, as will be evident from Figs. 2 and 3.Spaced from and extending substantially parallel to the wall N is a wall34 of a jacket. which also has the side walls 35 and similar end walls35 and 31 to provide a chamber in which the expansion coil is located,the expansion coil being spaced, however, from the walls thereof. saidwalls of' the jacket are provided with a covering 38 of heat insulatingmaterial, and said heat insulating material is, preferably, providedwith a metallic covering or sheath 39 on the outside thereof. Thechamber provided between the jacket and the wall It is filled with aheat transfer medium lll, which is indicated in the drawing as beingliquid, and which is of a liquid character 'when filled into saidchamber through a constantiy open fill pipe M at the upper end thereof,

a drain valve l2 being also provided for draining said heat transfermedium 40 from said chamber when this is desired.

Mounted on the jacket is an adjustable temperature. responsive orthermostatic controlling device ll, which may be of any well knowncharacter, and is provided'with a bulb 46, which extends through thewalls35 and 3 and the insulating material 38 into the chamber within thejacket incontact with the heat transfer'mediumfilled to the top thereofthrough the fill connection However. incase said material should expandin the liquid state, or be caused to surge about in the chamber, due tomovements of the dough mixer bowl, some of said heat transfer medium 40may spill through said fill opening. This is not only not objectionable,but will result in a slight air space being provided in the uppermostend of the chamber, which will prevent any knocking or hammering actionof the liquid 40 in case the" bowl is moved from one position toanother, thus avoiding any possibility of damage to the jacket becauseof such action of the liquid.

While the heat transfer medium 40 must be in a liquid state wheninserted into the chamben'it does not necessarily have to remain in'sucha liquid state, but can be of such a character that it will thicken oreven solidify at the temperatures which it reaches during operation ofthe device,

as the only important feature thereofr is that the same will transferheat and will thoroughly illl the space within the chamber around theexpansion coil and between the expansion coil and the walls of theJacket. However, if the material does solidify at such temperatures, itmust be of a character that no expansion thereof will take place uponsolidification thereof, as is the case of water or aqueous solutions. Ifaqueous solutions are used the same must be of such a character for thetemperatures reached by the heat transfer medium 40, that the same willremain in a liquid state with a certain margin of safety allowed.

While the temperature responsive controlling device 43 can be utilizedin any desired manner to control the operation of a refrigerating systemso that refrigerant is supplied to the expansion coil whenever thetemperature of the heat transfer medium 40 reaches a predeterminedmaximum, preferably, the arrangement shown in Fig.

1 is utilized. The thermostatic controlling means 43 may be of any wellknown character and is of the type that opens the circuit therethroughwhenever the temperature of the medium with which the bulb 44 is in heattransfer relation reaches a pre-determined minimum, and closes thecircuit therethrough whenever the temperature of the medium with whichthe bulb 44 is in heat transfer relation reaches a predeterminedmaximum. The controlling circuit shown in Fig. 1 comprises a pair ofconductors 45 and 46 leading from a suitable source of electricalenergy, which is not shown, the conductor 45 leading to the thermostaticcontrol 43, a conductor 41 leading from said control to theelectro-magnetic switch 26, and a conductor 48 leading from saidelectro-magnetic switch 26 tothe pressure controlled switch 28. Fromsaid pressure controlled switch 28 a conductor 49 leads to a magneticstarter switch 50, said conductor 46 also leading to said switch 56. Theclosing of the circuit including the conductors 46 and 49 acts to closethe magnetic starter switch 56 interposed be tween the line conductors5| and the conductors 52 leading to the motor 53, which drives thecompressor l6. A well known type of safety switch 54 is interposed inthe line conductors 5| providing for manual opening of the motor circuitwhen it is desired to throw the apparatus entirely out of operation.

The supply of refrigerant to the expansion coil can be either controlledthrough the magnetically operated valve 26 or the manually operatedvalve 22. If the manually operated valve 22 is only utilized, then theelectro-magnetic switch 26 is omitted from the system, and theconductors 41 through whenever the pressure in the suctionline 25 at theintake connection to the compressor l6 reaches a predetermined maximumand opens whenever said pressure in said suction line reaches apredetermined minimum. However, the switch 28 will not serve to operatethe compressor unless. the thermostatically controlled switch 43 is alsoclosed, due to the fact that the temperature of the heat transfer mediumhas reached a predetermined maximum. Accordingly, said pressurecontrolled switch and said temperature responsive switch 43 cooperate tocontrol the operation of the rotor 53 which drives the compressor l6. Inpractice, when a. batch of dough has been placed in the mixer to beoperated on, the compressor "5 will be started upon closing of theswitches 28 and 43 after a predetermined rise in temperature of the heattransfer medium 46 has taken place, and the pressure responsive switch23 will ordinarily not halt the operation of the compressor l6 due toopening thereof, but when the heat transfer medium 40 reaches apredetermined minimum temperature the controlllng circuit will be openedand the compressor [6 will be halted. Closingof the circuit willordinarily not again occur .until after the mixing operation has beencompleted, when, during a time that the mixer is not in use, there maybe a period of closing of the circuit to bring the mixer wall up to.the'temperature at which it is kept'while said mixer is empty. Theelectro-magnetically operated valve 26 will, of course, be opened whenthe controlling circuit is closed, so as to open the suction pipe'25 andpermit withdrawal of refrige iant by means of the compressor I6 from theexpansion coil. If the valve 26 is not. provided, then the suction linewill be constantly open and the with drawal of refrigerant will becontrolled entirely by the operation of the compressor. If it is desiredto entirely shut off the supply of refrigerant to the expansion coil themanually operated valve 22 is utilized for this purpose. I

Instead of providing an expansion coil of the r character shown in Fig.3, an expansion coil made up of pipe 29' can be provided, as shown inFig. 4, the expansion coil in this case being provided with means formounting the samebetween the jacket wall and the dough'mixer wall I4,such as the spacing members 55 and the heat transfer medium 40completely surrounding the expansion coil when an expansion coil of,this character is provided. The expansion coil in the form of theinvention shown in Fig. 4 is not in direct heat transfer relation to thedough mixer wall, but heat transfer is accomplished through the heattransfer medium 40.

What I claim is: I

1. In a dough mixer, a mixing chamber, rotatable beater arms in saidmixing chamber for contacting dough wlth a wall of said chamber, andmeans for cooling said wall comprising a jacket on the outer face ofsaid wall, a liquid heat transfer medium confined in said jacket,acooling coil within said jacket in engagement with said heat transfermedium, a compressor, a condenser, a receiver, conduit means connectingsaid coil, compressor, condenser and receiver in series in a closedcircuit, and temperature responsive means controlling the operation ofsaid compressor, having a temperature responsive controlling elementextending into said jacket, said temperature responsive element beinglocated in said liquid heat transfer medium remote from said wall andbeing exposed only thereto, said heat transfer medium being principallyin heat transfer relation to said coil and wall.

2. In a dough mixer, a mixing chamber, rotatable beater arms in saidmixing chamber for contacting dough with a wall of said chamber, andmeans for cooling said wall comprising a jacket on the outer face ofsaid wall, a heat transfer medium confined in said jacket, a coolingcoil substantially coextensive with said wall mounted on said wall inheat transfer relation thereto and within said jacket in engagement withsaid heat transfer medium, a compressor, a condenser, a receiver,conduit means connecting said coil, compressor, condenser and receiverin series in a closed circuit, and temperature responsive meanscontrolling the operation of said compressor, having a temperatureresponsive controlling element extendinginto said jacket and exposed tosaid heat transfer medium therein; said heat transfer medium-beingprincipally in heat transfer relation to said coil and wall.

3. In a dough mixer, a mixing chamber, rotatable beater arms in saidmixing; chamber for contacting dough with a wall of said chamber, andmeans for cooling said wall comprising a jacket on the outer face ofsaid wall, a liquid heat transfer medium confined in said jacket, acoolingcoil within said jacket surrounded by said heat transfer medium,a compressor, a condenser, a receiver, conduit means connecting saidcoil, compressor, condenser and receiver in series in a closed circult,and temperature responsive means controlling the operation of saidcompressor, having a temperature responsive controlling elementextending into said Jacket, said temperature responsive element beinglocated in said liquid heat transfer medium remote from said wall andbeing exposed only thereto, said heat transfer medium being principallyin heat transfer relation to said coil and wall.

lation principally with said coil and wall means for supplying andwithdrawing refrigerant from said coil, and a thermostatic control forsaid last mentioned means responsive to the temperature of said mediummounted in said liquid heat transfer medium in spaced relationto saidwall and coil.

MERLIN A. STICELBER.

REFERENCES crrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,699,576 Wolverton Jan. 22, 19292,219,789 Potte'r Oct. 29, 1940 2,274,220 Sticelber Feb. 24, 19422,323,354

